Attenuation of spontaneous thrombolytic activity measured by the global thrombosis test in male habitual smokers.

Smoking is known as one of the major risk factors for atherothrombotic cardiovascular diseases. We investigated the susceptibility to thrombosis in habitual smokers by using the global thrombosis test (GTT), by which both clot formation and clot lysis activities can be evaluated simultaneously in native blood samples in vitro. Subjects were 139 men participating in a periodic health checkup examination, and an informed consent for the subjects was obtained as a document. Using GTT, occlusion time (OT: the time taken for clot formation in the blood sample) and lysis time (LT: the time taken for lysis of the clot that had been formed) were measured. LT was significantly (p = 0.029) longer in smokers [median with range, 1,794 (1,080-6,000) s (n = 76)] than in nonsmokers [median with range, 1,530 (792-3,800) s (n = 63)], while there was no significant difference in OT between smokers and nonsmokers. In smokers, LT was significantly correlated with daily cigarette consumption but not with Brinkman index. LT measured in nine smokers at 3 months after quitting their habitual smoking was significantly shorter than LT measured before the cessation of smoking. Since prolongation of LT implies existence of thrombogenic tendency, smokers are thought to be more susceptible to thrombosis due to decreased fibrinolytic activity, and no smoking for even a short term may be effective for improving fibrinolytic activity in smokers.